Regulatory mechanisms of cytoskeletal proteins by phosphorylation and their cellular functions

我们发现Cdk1使vimentin- ser55从前期磷酸化到中期，导致Plk-1招募到vimentin。在与vimentin的Phospho-Ser55结合后，Plk1被激活，然后磷酸化vimentin- ser82。在细胞分裂过程中，rho激酶和Aurora-B特异性磷酸化卵裂沟中的IFs。Cdk1、Plk1、rho激酶和Aurora-B对中频的磷酸化在局部中频分解中起重要作用，并且对于中频网络有效分离到子细胞至关重要。我们也。发现Cdk1磷酸化内着丝粒蛋白（lNCENP）上的Thr59和Thr388。Cdk1对INCENP的磷酸化是Plk1向着丝点募集的必要条件，Plk1和Aurora-B在INCENP上形成复合物可能在染色体动力学调节中起关键作用。我们发现Trichoplein和Fas结合因子-1 （Fbf-I）是新的角蛋白结合蛋白。Trichoplein和Fbf-1有一个在trichohyalin/plectin之间序列相似性较低的结构域，称为trichohyalin/plectin homology domain （TPHD）。这些蛋白与角蛋白共定位，也定位于细胞-细胞粘附。

We found that Cdk1 phosphorylates vimentin-Ser55 from prometaphase to metaphase, leading to the recruitment of Plk-1 to vimentin. Upon binding to Phospho-Ser55 of vimentin, Plk1 is activated, and then phosphorylates vimentin-Ser82. During cytokinesis, Rho-kinase and Aurora-B specifically phosphorylate IFs at the cleavage furrow. The IF phosphorylation by Cdk1, Plk1, Rho-kinase, and Aurora-B plays an important role in the local IF breakdown, and is essential for the efficient segregation of IF networks into daughter cells. We also. found that Cdk1 phosphorylates Thr59 and Thr388 on inner centromere protein (lNCENP). INCENP phosphorylation by Cdk1 is necessary for the recruitment of Plk1 to the kinetochore, and the complex formation of Plk1 and Aurora-B on INCENP may play crucial roles in the regulation of chromosome dynamics. We identified Trichoplein and Fas binding factor-1 (Fbf-I) as novel keratin-binding proteins. Trichoplein and Fbf-1 have a domain that shows a low degree of sequence similarity between trichohyalin and plectin, designated, as trichohyalin/plectin homology domain (TPHD). These proteins co-localized with keratin, and also localized at cell-cell adhesion.